全双工通信关键技术研究

Key techniques research on full-duplex wireless communications

传统的半双工(half-duplex,HD)无线系统利用正交的时隙进行信号的发送和接收,造成无线频谱资源的极大浪费.而全双工(full-duplex,FD)通信技术以其链路容量倍增及其潜在的频谱资源利用率提升能力得到学术界和工业界的广泛关注.本文首先将全双工与半双工的模式性能进行比较,详细列举了现有全双工技术的优缺点.作为全双工系统的核心难题,自干扰(self-interference,SI)消除技术可以采用两类主要技术加以实现:被动自干扰抑制和主动自干扰消除.本文对相应技术的优缺点进行了比较.此外,针对复杂时变的无线频谱环境以及动态变化的无线网络结构,本文讨论了全双工媒体接入控制层(medium access control,MAC)协议的设计.本文还进一步论述了实际系统环境下的全双工算法设计与实现,包括中继网络编码、中继选择以及动态资源分配等.最后,本文对全双工通信未来研究方向进行了探讨,并总结全文.

Traditional half-duplex （HD） wireless systems transmit and receive signals adopting orthogonal time- slots, resulting in a great waste of frequency resources. And full-duplex （FD） wireless communication techniques have drawn extensive attention from academia and industry for the attractive abilities of doubling the channel capacity and promoting the utilization of spectrum resources. We frame the paper by first comparing the performance of HD and FD modes and addressing the advantages and disadvantages of the existing FD techniques. As the core problem of FD systems, self-interference （SI） cancellation will be realized by two main techniques： passive self-interference suppression and active self-interference cancellation. In this paper, we also present the advantages and disadvantages of respective techniques. Besides, the design of FD media access control （FD-MAC） layer is carried out based on the complex time-varying wireless spectrum environment and the dynamic wireless network structure. Furthermore, the design and implement of FD algorithms are presented in this paper, including relay network coding, relay selection and dynamic resource allocation. Finally, we sunmmrize the future research directions and conclnde the whole paper.